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Add ability to define download callback #1146

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Mar 12, 2020
Merged

Add ability to define download callback #1146

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1b1e21d
Add ability to define download callback
philippjfr Mar 12, 2020
8f39906
Update panel/widgets/misc.py
philippjfr Mar 12, 2020
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74 changes: 74 additions & 0 deletions examples/gallery/simple/save_filtered_df.ipynb
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Original file line number Diff line number Diff line change
@@ -0,0 +1,74 @@
{
"cells": [
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"import panel as pn\n",
"\n",
"from bokeh.sampledata.autompg import autompg\n",
"from io import StringIO\n",
"\n",
"pn.extension()"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"years = pn.widgets.MultiChoice(\n",
" name='Years', options=list(autompg.yr.unique()), margin=(0, 20, 0, 0)\n",
")\n",
"mpg = pn.widgets.RangeSlider(\n",
" name='Mile per Gallon', start=autompg.mpg.min(), end=autompg.mpg.max()\n",
")\n",
"\n",
"@pn.depends(years, mpg)\n",
"def filtered_mpg(yrs, mpg):\n",
" df = autompg\n",
" if years.value:\n",
" df = autompg[autompg.yr.isin(yrs)]\n",
" return df[(df.mpg >= mpg[0]) & (df.mpg <= mpg[1])]\n",
"\n",
"@pn.depends(years, mpg)\n",
"def filtered_file(yr, mpg):\n",
" df = filtered_mpg(yr, mpg)\n",
" sio = StringIO()\n",
" df.to_csv(sio)\n",
" sio.seek(0)\n",
" return sio\n",
"\n",
"fd = pn.widgets.FileDownload(\n",
" callback=filtered_file, filename='filtered_autompg.csv'\n",
")\n",
"\n",
"pn.Column(pn.Row(years, mpg), fd, pn.panel(filtered_mpg, width=600), width=600)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.7.5"
}
},
"nbformat": 4,
"nbformat_minor": 4
}
63 changes: 60 additions & 3 deletions examples/reference/widgets/FileDownload.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,9 @@
"##### Core\n",
"\n",
"* **``auto``** (boolean): Whether to download the file the initial click (if `True`) or when clicking a second time (or via the right-click Save file menu).\n",
"* **``callback``** (callable): A callable that returns a file or file-like object (takes precedence over `file` if set). \n",
"* **``embed``** (boolean): Whether to embed the data on initialization.\n",
"* **``file``** (str): A path to a filename.\n",
"* **``file``** (str or file-like object): A path to a file or a file-like object.\n",
"* **``filename``** (str): The filename to save the file as.\n",
"\n",
"##### Display\n",
Expand Down Expand Up @@ -87,7 +88,7 @@
"source": [
"pn.widgets.FileDownload(\n",
" file='FileDownload.ipynb', button_type='success', auto=False,\n",
" embed=True, name=\"Right-click to download using 'Save as' dialog\"\n",
" embed=False, name=\"Right-click to download using 'Save as' dialog\"\n",
")"
]
},
Expand All @@ -105,19 +106,75 @@
"outputs": [],
"source": [
"from bokeh.sampledata.autompg import autompg\n",
"\n",
"from io import StringIO\n",
"sio = StringIO()\n",
"autompg.to_csv(sio)\n",
"sio.seek(0)\n",
"\n",
"pn.widgets.FileDownload(sio, embed=True, filename='autompg.csv')"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"If you want to generate the file dynamically, e.g. because it depends on the parameters of some widget you can also supply a callback (which may be decorated with the widgets and/or parameters it depends on):"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"years = pn.widgets.MultiChoice(\n",
" name='Years', options=list(autompg.yr.unique()), margin=(0, 20, 0, 0)\n",
")\n",
"mpg = pn.widgets.RangeSlider(\n",
" name='Mile per Gallon', start=autompg.mpg.min(), end=autompg.mpg.max()\n",
")\n",
"\n",
"@pn.depends(years, mpg)\n",
"def filtered_mpg(yrs, mpg):\n",
" df = autompg\n",
" if years.value:\n",
" df = autompg[autompg.yr.isin(yrs)]\n",
" return df[(df.mpg >= mpg[0]) & (df.mpg <= mpg[1])]\n",
"\n",
"@pn.depends(years, mpg)\n",
"def filtered_file(yr, mpg):\n",
" df = filtered_mpg(yr, mpg)\n",
" sio = StringIO()\n",
" df.to_csv(sio)\n",
" sio.seek(0)\n",
" return sio\n",
"\n",
"fd = pn.widgets.FileDownload(\n",
" callback=filtered_file, filename='filtered_autompg.csv'\n",
")\n",
"\n",
"pn.Column(pn.Row(years, mpg), fd, pn.panel(filtered_mpg, width=600), width=600)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"pygments_lexer": "ipython3"
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.7.5"
}
},
"nbformat": 4,
Expand Down
10 changes: 5 additions & 5 deletions panel/param.py
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Original file line number Diff line number Diff line change
Expand Up @@ -559,14 +559,14 @@ def __init__(self, object=None, **params):
super(ParamMethod, self).__init__(object, **params)
self._link_object_params()
if object is not None:
self._update_inner(self._eval_function(object))
self._update_inner(self.eval(object))

#----------------------------------------------------------------
# Callback API
#----------------------------------------------------------------

@classmethod
def _eval_function(self, function):
def eval(self, function):
args, kwargs = (), {}
if hasattr(function, '_dinfo'):
arg_deps = function._dinfo['dependencies']
Expand All @@ -587,7 +587,7 @@ def _update_pane(self, *events):
self._callbacks = callbacks
self._link_object_params()
if object is not None:
self._update_inner(self._eval_function(self.object))
self._update_inner(self.eval(self.object))

def _link_object_params(self):
parameterized = get_method_owner(self.object)
Expand Down Expand Up @@ -618,7 +618,7 @@ def update_pane(*events):
self._callbacks.append(watcher)
for p in params:
deps.append(p)
new_object = self._eval_function(self.object)
new_object = self.eval(self.object)
self._update_inner(new_object)

for _, params in full_groupby(params, lambda x: (x.inst or x.cls, x.what)):
Expand Down Expand Up @@ -650,7 +650,7 @@ class ParamFunction(ParamMethod):
priority = 0.6

def _replace_pane(self, *args):
new_object = self._eval_function(self.object)
new_object = self.eval(self.object)
self._update_inner(new_object)

def _link_object_params(self):
Expand Down
33 changes: 22 additions & 11 deletions panel/widgets/misc.py
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -166,6 +166,9 @@ class FileDownload(Widget):
button_type = param.ObjectSelector(default='default', objects=[
'default', 'primary', 'success', 'warning', 'danger'])

callback = param.Callable(default=None, doc="""
A callable that return the file path or file-like object.""")

data = param.String(default=None, doc="""
The data being transferred.""")

Expand Down Expand Up @@ -209,7 +212,10 @@ class FileDownload(Widget):

_widget_type = _BkFileDownload

_rename = {'embed': None, 'file': None, '_clicks': 'clicks', 'name': 'title'}
_rename = {
'callback': None, 'embed': None, 'file': None,
'_clicks': 'clicks', 'name': 'title'
}

def __init__(self, file=None, **params):
self._default_label = 'label' not in params
Expand All @@ -227,7 +233,7 @@ def _update_default(self):
def _update_label(self):
label = 'Download' if self._synced or self.auto else 'Transfer'
if self._default_label:
if self.file is None:
if self.file is None and self.callback is None:
label = 'No file set'
else:
try:
Expand All @@ -239,33 +245,38 @@ def _update_label(self):
self.set_param(label=label)
self._default_label = True

@param.depends('embed', 'file', watch=True)
@param.depends('embed', 'file', 'callback', watch=True)
def _update_embed(self):
if self.embed:
self._transfer()

@param.depends('_clicks', watch=True)
def _transfer(self):
if self.file is None:
if self.file is None and self.callback is None:
return

from ..param import ParamFunction
filename = self.filename
if isinstance(self.file, str) and os.path.isfile(self.file):
with open(self.file, 'rb') as f:
if self.callback is None:
fileobj = self.file
else:
fileobj = ParamFunction.eval(self.callback)
if isinstance(fileobj, str) and os.path.isfile(fileobj):
with open(fileobj, 'rb') as f:
b64 = b64encode(f.read()).decode("utf-8")
if filename is None:
filename = os.path.basename(self.file)
elif hasattr(self.file, 'read'):
bdata = self.file.read()
filename = os.path.basename(fileobj)
elif hasattr(fileobj, 'read'):
bdata = fileobj.read()
if not isinstance(bdata, bytes):
bdata = bdata.encode("utf-8")
b64 = b64encode(bdata).decode("utf-8")
if self.filename is None:
if filename is None:
raise ValueError('Must provide filename if file-like '
'object is provided.')
else:
raise ValueError('Cannot transfer unknown file type %s' %
type(self.file).__name__)
type(fileobj).__name__)

ext = filename.split('.')[-1]
for mtype, subtypes in self._mime_types.items():
Expand Down